I don’t find SMART goals very effective. Achieving them feels hollow and pointless. Afterwards, I can never remember why I cared so much about this specific number on this specific date. They aren’t very motivating.
SMART goals are, however, the way to go if if you need a superficial way to evaluate the performance of a large team. You can slice through the nuance of circumstance, misfortune, and dumb luck with one grade.
A better approach for personal development is to create and fulfill an identity. Become the person you want to be, in your own eyes by making the right small daily decisions. The identity may also happen to achieve the number someone else wants, but that’s secondary to living your life in the way you find most fulfilling.
When one day, I’m golfing in my retirement village and someone asks me what I did for a living, I won’t say, “I made $XX by Y date.” I will say that I was a [identity] who valued Z and lived those values.